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BIOLOGY, M7 2024 HSC 22

A student designed and conducted a practical investigation to test for the presence of microbes in water and food samples.

  1. Justify a safety precaution required to prevent infection when conducting the investigation.   (2 marks)
  1. Explain how the student could ensure the reliability of the investigation.   (2 marks)

Show Answers Only

a.   Answers could include one of the following:

  • Wearing gloves when handling samples is essential to stop pathogens in the water/food entering through cuts or abrasions on bare hands, potentially causing infection.
  • Disinfecting all equipment after use is necessary because microbes can multiply rapidly and contaminated materials could spread infectious organisms to others in the laboratory. 

b.   To ensure the reliability of the investigation:

  • Student should prepare multiple food/water samples for testing to ensure consistent results across repeated trials.
  • This process allows them to verify if their findings are reproducible and reliable rather than due to chance.

Show Worked Solution

a.   Answers could include one of the following:

  • Wearing gloves when handling samples is essential to stop pathogens in the water/food entering through cuts or abrasions on bare hands, potentially causing infection.
  • Disinfecting all equipment after use is necessary because microbes can multiply rapidly and contaminated materials could spread infectious organisms to others in the laboratory. 

b.   To ensure the reliability of the investigation:

  • Student should prepare multiple food/water samples for testing to ensure consistent results across repeated trials.
  • This process allows them to verify if their findings are reproducible and reliable rather than due to chance.